A conventional method and a device for controlling an exhaust gas aftertreatment system of an internal combustion engine have been described, for example, in German Patent No. 199 06 287. In that reference, the exhaust gas aftertreatment system includes at least one particulate filter, which is used particularly in direct-injection internal combustion engines. In the method described, a state variable is recorded, which characterizes the state of the exhaust gas aftertreatment system, such as the loading state of the particulate filter. If this state variable, i.e. the loading of the particulate filter, exceeds certain values, the device initiates a special operating state in which the particle filter is regenerated by suitable measures. It is also provided that fuel reaches the exhaust gas tract, which is oxidized in an oxidizing catalytic converter, in order to raise the exhaust gas temperature.
For the initiation and/or for carrying out the regeneration of the particulate filter, additional fuel is required, which is either metered in using an additional metering device in the exhaust gas tract, or with the aid of the usual control elements for fuel injection. The disadvantage here is that the regeneration increases the fuel consumption. Moreover, it is possible that, because of the regeneration, the exhaust gas temperature in the particulate filter increases to impermissibly high values.